Automated printers (some of which produce line rather than alphanumeric images and are generally referred to as plotters) are usually controlled by computers and are capable of producing a wide variety of text, drawings, graphs, and other figures. Typically such printers print on a medium, such as paper, which is continuously fed either from roll form or from a fan-folded supply, such as that shown in U.S. Pat. No. 4,508,365--Hawes. Printing on something other than plain paper, to produce printed envelopes for example, may be accomplished by a combination of a fan-folded paper backer supply and the thing on which the print is to be made, e.g. envelopes as disclosed in U.S. Pat. No. 4,497,509--Gore.
While such printers are also useful to produce transparencies, that is transparent film sheets with images thereon suitable for projection, such transparent film sheets have not heretofore been available in convenient form particularly adapted for feeding (preferably in a continuous feed form) to an automatic printer or plotter.
One known attempt to provide a transparent film suitable for the making of transparencies on automatic printers embodied a fan-fold paper carrier web with individual transparent sheets removably adhered to individual sheets of the carrier web. This was found to be impractical because it was difficult to maintain the transparent sheet in registry with the paper backer during printing, using the separable adhesive, and also because the adhesive tended to leave a residue in the central window area of the film. This impaired the transparency of the film (after removal from the paper backer) and therefore its use as a transparent projection image. Transparencies thus produced also tended to be marked with fingerprints through handling of the film in the absence of a separate protector.
Another known transparency product is a continuous roll of film with tractor pin holes for feeding through a plotter. In addition to the difficulty in separating this continuous film media into individual sheets, other problems with this product include fingerprints on the transparency from handling and permanent curature of the film (resulting from its plastic memory of the roll form).